pngpal tool and first stab at embedding data on the EXE

WIP; the embedded data has an "environ" symbol that will cause issues
when we embed more than one piece of data.

9 files changed, 87 insertions, 8 deletions

diff --git a/Makefile b/Makefile
index 0c23670..8fbd78e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,17 +1,13 @@
 all:
-	#make -C tools
-	#make -C data
 	make -j -C src all
 
 run: all
 	dosbox -config dosbox.conf
 
 clean:
-	#make -C data clean
 	make -C src clean
 
 cleanall:
 	make -C src clean
-	#make -C tools clean
 
 .PHONY: all clean run
diff --git a/README.md b/README.md
index bdf738e..8a07d71 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,7 @@ Development:
 - GNU Make
 - DJGPP C (using GCC 12.1.0; other may work)
 - DOSBOX
+- tools: Python 3 and PIL (or Pillow) library
 
 For DJGPP I recommend cross-compilation using [build-djgpp](https://github.com/andrewwutw/build-djgpp/).
 
diff --git a/TODO.md b/TODO.md
index b7d7aad..b105713 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,7 +1,6 @@
 # TODO
 
 - drawing
-  - set palette
   - sw blitter
 - time
   - vga vsync
@@ -25,3 +24,4 @@
 
 # REVIEW
 
+- embeded data: remove the environ symbol!
diff --git a/data/sprites.png b/data/sprites.png
new file mode 100644
index 0000000..bfe73d4
--- /dev/null
+++ b/data/sprites.png
diff --git a/src/Makefile b/src/Makefile
index 94b83eb..a53c697 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -4,7 +4,7 @@ CFLAGS	:= -I. -c -Wall -pedantic -O2 -march=i386
 LDFLAGS := -s
 
 SRCS	:= $(wildcard *.c)
-OBJS	:= $(SRCS:.c=.o)
+OBJS	:= $(SRCS:.c=.o) palette.o
 
 all: $(BIN)
 
@@ -14,6 +14,9 @@ $(BIN): $(OBJS)
 .c.o:
 	$(CC) $(CFLAGS) $< -o $@
 
+palette.o: ../data/sprites.png
+	../tools/pngpal.py $< $@
+
 clean:
 	rm -f $(BIN) *.o Makefile.deps
 
diff --git a/src/main.c b/src/main.c
index 5b315df..dd3cffa 100644
--- a/src/main.c
+++ b/src/main.c
@@ -7,11 +7,16 @@
 
 #include "vga.h"
 
+/* embedded data */
+extern const uint8_t binary_palette_start[];
+
 int main(int argc, char *argv[])
 {
     /* set VGA 320x200, 256 col */
     set_mode(0x13);
 
+    set_palette(binary_palette_start);
+
     uint8_t *screen = open_framebuffer();
     if (!screen)
     {
@@ -19,8 +24,11 @@ int main(int argc, char *argv[])
         return 1;
     }
 
-    for (int i = 0; i < 320 * 200 * 10; i++)
-        screen[rand() % (320 * 200)] = rand() % 255;
+    for (int i = 0; i < 16; i++)
+    {
+        memset(screen, i, 320 * 200);
+        getch();
+    }
 
     printf("Hello DOS!\n");
 
diff --git a/src/vga.c b/src/vga.c
index 5badd82..b3ee0a2 100644
--- a/src/vga.c
+++ b/src/vga.c
@@ -2,6 +2,7 @@
 #include <stdint.h>
 #include <dpmi.h>
 #include <sys/nearptr.h>
+#include <pc.h>
 
 uint8_t *open_framebuffer()
 {
@@ -22,3 +23,10 @@ void set_mode(uint8_t mode)
     regs.x.ax = mode;
     __dpmi_int(0x10, &regs);
 }
+
+void set_palette(const uint8_t *palette)
+{
+    outportb(0x3c8, 0);
+    for (int i = 0; i < 768; i++)
+        outportb(0x3c9, (palette[i] * 63) / 255);
+}
diff --git a/src/vga.h b/src/vga.h
index f35e6dd..a9c46c6 100644
--- a/src/vga.h
+++ b/src/vga.h
@@ -6,4 +6,7 @@ void close_framebuffer();
 
 void set_mode(uint8_t mode);
 
+/* the palette is expected to be 8 bit per color, and will be converted to VGA's 6 bit per color */
+void set_palette(const uint8_t *palette);
+
 #endif // _VGA_H
diff --git a/tools/pngpal.py b/tools/pngpal.py
new file mode 100755
index 0000000..7db451d
--- /dev/null
+++ b/tools/pngpal.py
@@ -0,0 +1,60 @@
+#!/usr/bin/env python3
+
+from argparse import ArgumentParser
+import subprocess
+import os
+from PIL import Image
+
+__version__ = "1.0"
+
+ld = os.environ.get("LD", "i586-pc-msdosdjgpp-ld")
+
+
+def main():
+    parser = ArgumentParser(
+        description="PNG to palette .o",
+        epilog="Copyright (C) 2023 Juan J Martinez <jjm@usebox.net>",
+    )
+
+    parser.add_argument(
+        "--version", action="version", version="%(prog)s " + __version__
+    )
+    parser.add_argument("image", help="image to convert")
+    parser.add_argument("output", help="objtect name for the palette")
+
+    args = parser.parse_args()
+
+    try:
+        image = Image.open(args.image)
+    except IOError:
+        parser.error("failed to open the image")
+
+    if image.mode != "P":
+        parser.error("not an indexed image (no palette)")
+
+    palette = image.getpalette()
+    if not palette:
+        parser.error("failed to extract the palette")
+
+    tmp = args.output.rstrip(".o")
+    with open(tmp, "wb") as fd:
+        fd.write(bytearray(palette))
+        fd.flush()
+        rc = subprocess.call(
+            [
+                ld,
+                "-r",
+                "-b",
+                "binary",
+                "-o",
+                args.output,
+                tmp,
+            ]
+        )
+        os.unlink(tmp)
+        if rc != 0:
+            parser.error("Failed to run %s" % ld)
+
+
+if __name__ == "__main__":
+    main()